Method and apparatus for reduced flash encapsulation of microelectronic devices

ABSTRACT

A method and apparatus for encapsulating microelectronic devices. In one embodiment, a microelectronic device is engaged with a support member having a first edge, a second edge opposite the first edge, and an engaging surface with at least a portion of the engaging surface spaced apart from the first and second edges. The first edge of the support member is positioned proximate to a wall of a mold and an aligning member is moved relative to the wall of the mold to contact the engaging surface of the support member and bias the first edge of the support member against the wall of the mold. The microelectronic device is then encapsulated by disposing an encapsulating material in the mold adjacent to the microelectronic device. By biasing the first edge of the support member against the wall of the mold, the method can prevent encapsulating material from passing between the first edge of the support member and the wall of the mold, where the encapsulating material would otherwise form flash. Accordingly, a method and apparatus in accordance with an embodiment of the invention can reduce or eliminate flash adjacent to the first edge of the support member.

TECHNICAL FIELD

[0001] This invention relates to methods and apparatuses for packagingmicroelectronic devices with reduced flash.

BACKGROUND

[0002] Packaged microelectronic assemblies, such as memory chips andmicroprocessor chips, typically include a microelectronic device mountedto a substrate and encased in a plastic protective covering. The deviceincludes functional features, such as memory cells, processor circuits,and interconnecting circuitry. The device also typically includes bondpads electrically coupled to the functional features. The bond pads arecoupled to pins or other types of terminals that extend outside theprotective covering for connecting the microelectronic device to busses,circuits and/or other microelectronic assemblies.

[0003] In one conventional arrangement, shown in FIG. 1, a device 40 ismounted to a substrate 20, such as a printed circuit board (“PCB”). Thesubstrate 20 and the device 40 are placed in a mold 50 forencapsulation. The mold 50 can include an upper portion 51 removablyattached to a lower portion 52 to define a device cavity 57, a pelletcavity 54, and a runner cavity 56 extending between the device cavity 57and the pellet cavity 54. The substrate 20 is clamped between the upperportion 51 and the lower portion 52 with the device 40 positioned in thedevice cavity 57. A pellet of mold compound 60 is placed in the pelletcavity 54 and a plunger 55 forces the pellet 60 into the device cavity57 via the runner cavity 56 to encapsulate the device 40.

[0004] Referring now to FIGS. 1 and 2, the substrate 20 has a first edge21, a second edge 22 opposite the first edge 21, and drilled indexingholes 23 along both edges 21 and 22. The indexing holes 23 along thesecond edge 22 receive undersized index pins 53 when the substrate 20 isplaced in the mold 50. An alignment pin 70 engages the second edge 22and forces the substrate 20 toward the right (as seen in FIG. 1) so thatthe first edge 21 of the substrate 20 approaches an edge 59 of the mold50 as the upper portion 51 and the lower portion 52 of the mold 50 movetoward each other.

[0005] In one aspect of this conventional arrangement, the first edge 21and the second edge 22 of the substrate 20 are routed with a router toolor formed by other low-cost processes. Accordingly, a width 29 of thesubstrate 20 between the first and second edges 21 and 22 can have atolerance of ±100 microns. One drawback with this approach is that thedimensional tolerance of the width 29 can lead to damaging the substrate20 and/or forming flash around the encapsulated device 40. For example,if the substrate 20 has a width 29 toward the upper end of the tolerancerange, it can buckle and/or break when the alignment pin 70 forces thesubstrate 20 against the mold edge 59. Conversely, if the substrate 20has a width 29 toward the lower end of the tolerance range, a gap G canremain between the first edge 21 of the substrate and the mold edge 59,even after the alignment pin 70 has moved the substrate 20 toward theright. The gap G can fill with mold compound, creating a flange of flashextending outwardly from the first edge 21 of the substrate 20. Theflash can interfere with subsequent processing steps, for example bycatching on processing machines, or by separating from the substrate 20and contaminating the machines.

SUMMARY

[0006] The present invention is directed toward methods and apparatusesfor encapsulating microelectronic devices. A method in accordance withone aspect of the invention includes providing a support member having afirst edge, a second edge opposite the first edge, and an engagingsurface with at least a portion of the engaging surface spaced apartfrom the first and second edges. The method can further include engagingthe microelectronic device with the support member, positioning thefirst edge of the support member proximate to a wall of a mold, movingan aligning member relative to the wall of the mold and biasing thefirst edge of the support member against the wall of the mold byengaging the aligning member with the portion of the engaging surfacespaced apart from the first and second edges. The method can furtherinclude at least partially encapsulating the microelectronic device bydisposing an encapsulating material in the mold adjacent to themicroelectronic device.

[0007] In a further aspect of the invention, the method can includeforming the engaging surface to be spaced apart from the first surfaceof the support member by a selected distance having a tolerance of ±50microns or less. Biasing the first edge of the support member againstthe wall of the cavity can include moving the aligning member in adirection either transverse to or aligned with a surface of the supportmember engaged with the microelectronic device.

[0008] The invention is also directed to a support member and method forforming a support member to support a microelectronic device. Thesupport member can include a first edge configured to engage an interiorwall of the mold, a second edge opposite the first edge, an electricallyconductive material between the first and second edges for coupling tothe microelectronic device, and an engaging surface. In one embodiment,the engaging surface is spaced apart from the first edge by a selecteddistance having a tolerance of ±50 microns or less and is configured toengage an alignment member of the mold when the support member and themicroelectronic device are placed in the mold with the first edge of thesupport member engaged with the interior wall of the mold.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a partially schematic, cross-sectional side elevationalview of a support member supporting a microelectronic device in a moldin accordance with the prior art.

[0010]FIG. 2 is a top plan view of the support member shown in FIG. 1.

[0011]FIG. 3 is a top plan view of a support member having engagingsurfaces in accordance with an embodiment of the invention.

[0012]FIG. 4 is a cross-sectional side elevational view of the supportmember taken substantially along line 4-4 of FIG. 3 and installed in amold apparatus having an alignment pin in accordance with an embodimentof the invention.

[0013]FIG. 5 is a top plan view of a support member having engagingsurfaces in accordance with another embodiment of the invention.

[0014]FIG. 6 is a top plan view of a support member having straightengaging surfaces in accordance with yet another embodiment of theinvention.

[0015]FIG. 7 is a top plan view of a support member having straight,recessed engaging surfaces in accordance with another embodiment of theinvention.

[0016]FIG. 8 is a top isometric view of an alignment pin having astraight tapered surface in accordance with still another embodiment ofthe invention.

[0017]FIG. 9 is a top isometric view of an alignment pin having flattapered surfaces in accordance with yet another embodiment of theinvention.

[0018]FIG. 10 is a top isometric view of an alignment pin having asharpened edge in accordance with still another embodiment of theinvention.

[0019]FIG. 11 is a top plan view of an assembly of substrates havingengaging surfaces formed in accordance with another embodiment of theinvention.

[0020]FIG. 12 is a cross-sectional side elevational view of a supportmember positioned in a mold apparatus having an alignment pin that movestransversely in accordance with another embodiment of the invention.

DETAILED DESCRIPTION

[0021] The present disclosure describes packaged microelectronic devicesand methods for packaging such devices. Many specific details of certainembodiments of the invention are set forth in the following descriptionand in FIGS. 3-11 to provide a thorough understanding of theseembodiments. One skilled in the art, however, will understand that thepresent invention may have additional embodiments, or that the inventionmay be practiced without several of the details described below.

[0022]FIG. 3 is a top plan view of a support member 120 having twoengaging surfaces 130 in accordance with an embodiment of the invention.In one aspect of this embodiment, the support member 120 has an uppersurface 124, a lower surface 125 facing opposite the upper surface 124,and first and second edges 121 and 122 between the upper surface 124 andthe lower surface 125. Index holes 123 having a small diameter (e.g.,1.5 mm) are positioned along the edges 121 and 122. The support member120 can include a generally non-conductive material, such as a plastic,epoxy or glass-impregnated bismalimide triazine with conductive layersand/or vias for routing electrical signals from one portion of thesupport member 120 to another.

[0023] In a further aspect of this embodiment, each engaging surface 130defines a curved, semi-circular alignment aperture or notch 131 formedin the second edge 122. In yet a further aspect of the embodiment, eachalignment aperture 131 extends completely through the support member 120from the upper surface 124 to the lower surface 125. Alternatively, thealignment apertures 131 and the engaging surfaces 130 can have otherconfigurations, such as those described below with reference to FIGS. 5,6 and 12.

[0024] In one embodiment, the first edge 121 and each engaging surface130 is separated by a separation distance 128 (measured along a lineperpendicular to both the first edge 121 and the engaging surface 130)having a dimension that is held to a tolerance of less than ±100microns. For example, in one aspect of this embodiment, the distance 128is held to a tolerance of ±50 microns. Alternatively, the tolerance bandcan have other values greater or less than ±50 microns, so long as thetolerance band is less than ±100 microns.

[0025] In one embodiment, the engaging surfaces 130 can be formed with aconventional mechanical drill bit and the alignment apertures 131 canhave a radius of approximately one half the tolerance band of thedistance 128. For example, when the tolerance band is ±50 microns, theradius of the alignment aperture 131 can be at least 50 microns, and themechanical drill bit can have a corresponding radius of approximately 50microns. Alternatively, the drill bit and the alignment aperture canhave other radii in other embodiments. For example, in one embodiment, adrill bit having radius of about 2500 microns is used for simultaneouslydrilling through a stack of five support members 120 to producealignment apertures 131 spaced apart from the first edge 121 of thesupport member 120 by a distance 128 having a tolerance of ±50 microns.Alternatively, the drill bit can be larger or smaller than 2500 micronsfor drilling through one or more support members 120. For example, thedrill bit radius may be larger for tolerances tighter than ±50 micronsand/or for drilling through more than five support members 120, becausea larger drill bit tends to “wander” less than a smaller drill bit as itcuts through a stack of support members. Alternatively, a smaller drillbit may be used when simultaneously drilling through fewer than fivesupport members 120.

[0026] In other embodiments, the engaging surfaces 130 can be formedwith other techniques. For example, the engaging surfaces 130 can beformed with a water jet or a laser beam that impinges the support member120. In still further embodiments, the engaging surfaces 130 can beformed with other processes that hold the separation distance 128 towithin a tolerance of less than ±100 microns.

[0027]FIG. 4 is a cross-sectional side elevational view of the supportmember 120 (taken substantially along line 4-4 of FIG. 3) attached to amicroelectronic device 140 and positioned in a mold apparatus 150 inaccordance with an embodiment of the invention. In one aspect of thisembodiment, the mold apparatus 150 includes an upper mold portion 151removably coupled to a lower mold portion 152 with the support member120 clamped therebetween. The device 140 is received in a device cavity157 that is coupled to a pellet cavity 154 with a runner cavity 156.Pellets of encapsulating mold material (not shown) are heated andpressurized in the pellet cavity 154 and forced into the runner cavity156 and the device cavity 157 to encapsulate the device 140 and aportion of the support member 120 in a manner generally similar to thatdescribed above.

[0028] In one aspect of an embodiment shown in FIG. 4, the lower moldportion 152 includes a gate 158 that provides a weak point in theencapsulated mold material for breaking a runner portion of the moldmaterial off from the encapsulated device 140. The lower mold portion152 can also include index pins 153 that are loosely received in theindex holes 123 of the support member 120. Accordingly, the index pins153 do not snugly engage the walls of the index holes 123. This featurereduces the likelihood that the index holes 123 will be deformed duringthe molding process. Therefore, the index holes 123 can more accuratelyposition the support member 120 in subsequent process steps.

[0029] In another aspect of an embodiment of the mold apparatus 150shown in FIG. 4, the upper mold portion 151 includes two taperedalignment pins or members 170, one of which is visible in FIG. 4. Eachalignment pin 170 is snugly received in a receiving aperture 171 in thelower mold portion 152 when the upper and lower mold portions 151 and152 are brought together. Referring now to FIGS. 3 and 4, as thealignment pins 170 descend into the receiving apertures 171, the taperedouter surface of each alignment pin engages one of the engaging surfaces130 of the support member 120 and gradually drives the support member120 toward the right (as seen in FIG. 4). Accordingly, the alignmentpins 170 move transverse to the plane of the support member. As usedherein, “transverse” refers to any non-aligned angle, including a rightangle. When the upper and lower mold portions 151 and 152 clamp againstthe opposite surfaces 124 and 125 of the support member 120, the firstedge 121 of the support member 120 is biased firmly against a mold edge159 of the lower mold portion 152 to prevent or at least significantlyrestrict mold material from squeezing between the first edge 121 and themold edge 159.

[0030] In one embodiment, each alignment pin 170 has an externalalignment surface that includes a cylindrical shank 172 and a roundedend portion 174. The shank 172 and the end portion 174 can alternativelyhave other shapes, as described below with reference to FIGS. 8-10. In afurther aspect of an embodiment shown in FIG. 4, the radius R of eachalignment pin 170 is at least half the tolerance band or range of thedistance 128 between the engaging surface 130 and the first edge 121 ofthe support member 120. For example, when the tolerance band is ±50microns, the radius R of the shank 172 is at least 50 microns.Accordingly, when the distance 128 is undersized by 50 microns, theshank 172 contacts the engaging surfaces 130 of the support member 120,and the first edge 121 of the support member 120 just seals against themold edge 159, when the mold portions 151 and 152 are brought togetherand the alignment pin 170 bottoms out in the receiving aperture 171.

[0031] When the distance 128 is neither oversized nor undersized (i.e.,the distance 128 is at the center of the tolerance band), a tip 176 oranother part of the end portion 174 of each alignment pin 170 engagesthe corresponding engaging surface 130 as each alignment pin 170 beginsits descent into the receiving aperture 171, while the first edge 121contacts the mold edge 159. As the alignment pins 170 move into thereceiving apertures 171, they drive the first edge 121 of the supportmember 120 against the mold edge 159, compressing the support member 120by about 50 microns and sealing the interface between the support member120 and the mold edge 159. When the distance 128 is oversized by 50microns, the operation is generally similar, except that the supportmember 120 is compressed by about 100 microns. In other embodiments, thesize of the alignment pins 170 and the apertures 131 defining theengaging surfaces 130 can have other values (depending on the size ofthe tolerance band) that allow the support member 120 to be sealedagainst the mold edge 159 regardless of where (within the toleranceband) the distance 128 falls.

[0032] In one embodiment, the first edge 121 of the support member 120is biased against the mold edge 159 with a firm but relatively lightforce when the support member 120 is undersized (i.e., when the distance128 is toward the lower end of the tolerance band). When the supportmember is oversized (i.e., when the distance 128 is toward the upper endof the tolerance band), the alignment pins 170 exert a greater force onthe support member 120, but not so great a force as to break orunacceptably buckle the support member 120. Regardless of where withinthe tolerance band the distance 128 falls, the amount of biasing forceapplied by the alignment pins 170 is independent of the overall width129 (FIG. 3) of the support member 120, so long as the support member120 fits in the mold apparatus 150.

[0033] In one aspect of an embodiment of the mold apparatus 150, theupper mold portion 151 includes two alignment pins 170, each positionedto engage a corresponding one of the spaced-apart engaging surfaces 130.Accordingly, each alignment pin 170 can prevent the support member 120from rotating about the other alignment pin 170. Alternatively, theupper mold portion 151 can include a single alignment pin 170 alignedwith a single engaging surface 130 positioned at, or very near, thecenter of the first surface 121 of the support member 120. Accordingly,the single alignment member 170 will impart a force but no moment to thesupport member 120. In another alternate embodiment, the upper moldportion 151 can include more than two alignment pins 170 and the supportmember 120 can include more than two engaging surfaces 130, as describedbelow with reference to FIG. 5.

[0034] One feature of an embodiment of the support member 120 and themold apparatus 150 described above with reference to FIGS. 3 and 4 isthat the distance 128 between the engaging surfaces 130 and the firstedge 121 of the support member 120 can be formed to have a tolerance ofless than ±100 micron. An advantage of this feature is that supportmembers 120 that are oversized (but still within the tolerance band),can be accommodated by the mold apparatus 150 without breaking orexcessively warping. Furthermore, support members 120 that areundersized (but still within the tolerance band), can be accommodated inthe mold apparatus 150 without leaving a gap between a first edge 121 ofthe support members 120 and the mold edge 159. Accordingly, thelikelihood for forming flash at the first edge 121 of the support member120 is eliminated or at least substantially reduced.

[0035] Another feature of an embodiment of the support member 120 andthe mold apparatus 150 described above with reference to FIGS. 3 and 4is that the engaging surfaces 130 need only extend for a short lengthalong the second edge 122 of the support member 120. An advantage ofthis feature is that relatively inexpensive fabrication techniques canbe used to form the remaining length of the second edge 122 and theentire length of the first edge 121. For example, the first and secondedges 121 and 122 can be routed in a conventional, relatively low costprocess, while the engaging surfaces 130 can be precision drilled withmechanical drill bits, laser beams or water jets.

[0036] In an alternate embodiment, both the engaging surfaces 130 andthe first edge 121 can be precision formed, for example with a laserbeam or a water jet, to reduce the tolerance band corresponding to thedistance 128. The remaining edges of the substrate 120 can then beformed with lower cost processes, such as routing. An advantage of thisalternate embodiment is that the likelihood for breaking and/or warpingthe substrate 120, and/or creating flash along the first edge 121 of thesubstrate 120, can be reduced even further when compared to conventionaltechniques for forming the substrate 120, without requiring precisiontechniques to form all the edges of the substrate 120. Conversely, anadvantage of precision forming only the engaging surfaces 130 is thatthis process can be less time consuming than precision forming both theengaging surfaces 130 and the first edge 121.

[0037]FIG. 5 is a top plan view of a support member 220 having a firstedge 221, a second edge 222, and three engaging surfaces 230 formed inaccordance with another embodiment of the invention. In one aspect ofthis embodiment, each engaging surface 230 forms a portion of anenclosed alignment aperture 231 that is spaced apart from the first edge221. A distance 228 between the engaging surfaces 230 and the first edge221 can be held to tolerances generally similar to those described abovewith reference to FIGS. 3 and 4. Each alignment aperture 231 can includea facing surface 232 facing opposite the engaging surface 231. Thedistance between the facing surface 232 and either the first edge 221 orthe second edge 222 of the support member 220 need not be carefullycontrolled to properly align the support member 220 in the moldapparatus 150 described above with reference to FIG. 4. Accordingly, thefacing surface 232 can have any position relative to the edges 221 and222, and the alignment aperture 231 can have any shape (e.g., round,elliptical, rectangular), so long as the position of the engagingsurface 230 relative to the first edge 221 is within the tolerance bandsdescribed above with reference to FIGS. 3 and 4.

[0038] One feature of an embodiment of the support member 220 shown inFIG. 5 is that the support member 220 includes three alignment apertures231. An advantage of this arrangement (when compared to the supportmember 120 described above with reference to FIGS. 3 and 4) is that thesupport member 220 may be less likely to rotate or otherwise shiftwithin the mold apparatus 150 because it can be engaged by up to threealignment pins. Conversely, an advantage of the embodiment of thesupport member 120 is that it can be less expensive to manufacture thanan embodiment of the support member 220 because it has fewer engagingsurfaces.

[0039]FIG. 6 is a top plan view of a support member 320 a having a firstedge 321, a second edge 322 opposite the first edge 321, and twostraight engaging surfaces 330 a in accordance with another embodimentof the invention. In one aspect of this embodiment, each engagingsurface 330 a defines the outer edge of a tab 333 that projectsoutwardly from the second edge 322 of the support member 320 a. Eachengaging surface 330 a can be offset from the first edge 321 of thesupport member 320 a by a distance 328 a having a tolerance band withinthe range described above with reference to FIGS. 3 and 4. In one aspectof this embodiment, the support member 320 a can be sealed against anedge of a mold by alignment pins generally similar to the alignment pins170 described above with reference to FIG. 4, but having a flat outersurface (rather than the rounded surface shown in FIG. 4) that contactthe flat engaging surfaces 330 a. Such alignment pins are described ingreater detail below with reference to FIG. 9.

[0040]FIG. 7 is a top plan view of another embodiment of a supportmember 320 b having recessed straight engaging surfaces 330 b. Eachengaging surface 330 b forms one edge of a rectangular cutout in thesecond edge 322 of the support member 320 b. The engaging surfaces 330 bcan be spaced apart from the first edge 321 of the support member 320 bby a distance 328 b having a tolerance band within the range describedabove with reference to FIGS. 3 and 4.

[0041]FIG. 8 is a top isometric view of an alignment pin 470 having ahead 473, a shank 472 below the head 473, and a tapered end portion 474in accordance with an embodiment of the invention. In one aspect of thisembodiment, the alignment pin 470 is shaped to be positioned in theupper portion 151 of the mold apparatus 150 described above withreference to FIG. 4. In a further aspect of this embodiment, the taperedend portion 474 can have a conical shape. Alternatively, the tapered endportion 474 can have a more rounded or parabolic shape, as shown in FIG.4. In other embodiments, the tapered end portion 474 can have othershapes that are configured to engage the engaging surface 130 of thesupport member 120 and bias the support member 120 against the mold edge159 described above with reference to FIG. 4.

[0042]FIG. 9 is a top isometric view of an alignment pin 570 having arectangular shank 572 and a pyramidal tapered end portion 574.Accordingly, the alignment pin 570 can engage the recessed, straightengaging surface 330 b of the support member 320 b, described above withreference to FIG. 7. The alignment pin 570 can also engage otherstraight engaging surfaces, such as the outwardly projecting engagingsurfaces 330 a described above with reference to FIG. 6. For example, inone aspect of this embodiment, the shank 572 can have a recess 575 sizedto fit around at least a portion of the tab 333 shown in FIG. 6.

[0043]FIG. 10 is a top isometric view of an alignment pin 670 having ashank 672, a tapered end portion 674, and a sharpened edge 675 inaccordance with another embodiment of the invention. In one aspect ofthis embodiment, the sharpened edge 675 is sharp enough to pierce theengaging surface of any of the support members described above withreference to FIGS. 3-7. Accordingly, the alignment pin 670 can be shapedto engage a curved or straight engaging surface, depending upon theconfiguration of the support member. An advantage of the sharpened edge675 is that it can relieve stresses in the support member that may becreated as the support member is biased against the mold edge 159 (FIG.4). Accordingly, the support member may be less likely to buckle orbreak as it is biased against the mold edge 159. Conversely, anadvantage of alignment pins that do not pierce the engaging surfaces isthat they may be less likely to form cracks or splits in the supportmember as they bias the support member against the mold edge 159.

[0044]FIG. 11 is a top plan view of a support member assembly 720 thatincludes a sheet of support member material configured to be singulatedinto a plurality of support members (shown as left support members 720 aadjacent to right support members 720 b). The support members 720 a and720 b are separated from each other by singulating the support memberassembly 720 along singulation axes 726. Accordingly, each left supportmember 720 a has a first edge 721 a and a second edge 722 a, and eachright support member 720 b has a first edge 721 b and a second edge 722b. In one aspect of this embodiment, the second edge 722 a of each leftsupport member 720 a is positioned adjacent the second edge 722 b of theadjacent right support member 720 b. Accordingly, a plurality ofalignment apertures 731 can be formed in the support member assembly 720to straddle the singulation axes 726 between the second edges 722 a and722 b of adjacent support members. Each alignment aperture 731 thereforeincludes a left engaging surface 730 a in one of the left supportmembers 720 a and a right engaging surface 730 b in the adjacent rightsupport member 720 b.

[0045] In one embodiment, the alignment apertures 731 can be formed withmechanical drill bits, or alternatively the alignment apertures 731 canbe formed with water jets, lasers or other suitable methods. In any ofthese embodiments, an advantage of this arrangement is that eachalignment aperture 731 forms two engaging surfaces. Accordingly, thecost for forming the support members 720 a and 720 b can be reduced byreducing the number of machining operations required to form thealignment apertures 731.

[0046]FIG. 12 is a cross-sectional side elevational view of a supportmember 820 positioned in a mold apparatus 850 in accordance with anotherembodiment of the invention. In one aspect of this embodiment, thesupport member 820 includes a first edge 821, a second edge 822, anupper surface 824, a lower surface 825, and an alignment aperture 831that extends part-way through the support member 820 from the uppersurface 824. Accordingly, the alignment aperture 831 can have anaperture end 834 that is offset from both the upper surface 824 and thelower surface 825 of the support member 820. The alignment aperture 831defines an engaging surface 830 that extends from the upper surface 824to the aperture end 834 and is formed such that a distance between thealignment aperture 831 and the first edge 821 is within the tolerancerange described above with reference to FIGS. 3 and 4.

[0047] In another aspect of this embodiment, the mold apparatus 850 caninclude an upper portion 851, a lower portion 852 and an alignment pin870 that translates toward the second edge 822 of the support member 820to contact the engaging surface 831 and bias a first edge 821 of thesupport member 820 against a mold edge 859 of the mold apparatus 850.For example, the alignment pin 870 can move from left to right asindicted by arrow 877 to engage and bias the support member 820. In afurther aspect of this embodiment, the alignment pin 870 can be lockedin place once it is in the biased position. In still a further aspect ofthis embodiment, the alignment pin need not include a tapered end, butcan instead have a generally straight shank 872 for engaging the supportmember 820.

[0048] From the foregoing it will be appreciated that specificembodiments of the invention have been described herein for purposes ofillustration, but that various modifications may be made withoutdeviating from the spirit and scope of the invention. Accordingly, theinvention is not limited except as by the appended claims.

1. A method for encapsulating a microelectronic device, comprising:engaging the microelectronic device with a support member having a firstedge, a second edge opposite the first edge, and an engaging surfacewith at least a portion of the engaging surface spaced apart from thefirst and second edges; positioning the first edge of the support memberproximate to a wall of a mold; biasing the first edge of the supportmember against the wall of the mold by engaging an aligning member withthe portion of the engaging surface spaced apart from the first andsecond edges; and at least partially encapsulating the microelectronicdevice by disposing an encapsulating material in the mold adjacent tothe microelectronic device.
 2. The method of claim 1, further comprisingpreventing the encapsulating material from passing between the firstedge of the support member and the wall of the mold by forming a sealbetween the first edge of the support member and the wall of the mold.3. The method of claim 1 wherein engaging the microelectronic devicewith a support member includes engaging the microelectronic device witha support member having a concave aperture in the second edge of thesupport member, a wall of the concave aperture defining the engagingsurface.
 4. The method of claim 1 wherein engaging the microelectronicdevice with a support member includes engaging the microelectronicdevice with a support member having an engaging surface defined at leastin part by an aperture extending through the support member and spacedapart from the first and second edges.
 5. The method of claim 1 whereinthe aligning member includes an alignment surface that tapers relativeto the wall of the mold, further comprising: engaging themicroelectronic device with a support surface of the support memberpositioned between the first and second edges of the support member; andmoving the alignment surface of the aligning member along the engagingsurface of the support member in a direction transverse to a plane ofthe support surface.
 6. The method of claim 1, further comprisingcutting into the engaging surface of the support member with thealigning member.
 7. The method of claim 1 wherein the mold has a firstportion with the wall and a second portion separable from the firstportion along a mold line, the second portion having the aligningmember, further comprising positioning the support member and themicroelectronic device between the first and second portions of the moldand moving at least one of the first and second portions toward theother to engage the aligning member with the support member.
 8. Themethod of claim 1, further comprising forming the portion of theengaging surface that contacts the aligning member to be spaced from thefirst surface by a selected distance having a tolerance of ±50 micronsor less.
 9. The method of claim 1 wherein engaging the microelectronicdevice with a support member includes engaging the microelectronicdevice with a support member having a tab extending away from the secondedge of the support member, with the engaging surface defined by asurface of the tab.
 10. The method of claim 1 wherein biasing the firstedge of the support member includes moving the aligning membertransverse to a surface of the support member engaged with themicroelectronic device.
 11. The method of claim 1 wherein biasing thefirst edge of the support member includes moving the aligning member ina direction generally aligned with a surface of the support memberengaged with the microelectronic device.
 12. The method of claim 1wherein engaging the microelectronic device with a support memberincludes engaging the microelectronic device with a support memberhaving an aperture open to the second edge of the support member.
 13. Amethod for encapsulating a microelectronic device, comprising: engagingthe microelectronic device with a support member having a first edge, asecond edge opposite the first edge, and a concave recess in the secondedge; positioning the support member with the first edge proximate to aninterior wall of a mold; sealing the first edge of the support memberagainst the interior wall of the mold by biasing the support membertoward the interior wall of the mold with a pin extending transverse tothe second edge of the support member and engaged with the concaverecess of the support member; and supplying an encapsulating material tothe mold to at least partially encapsulate the microelectronic device.14. The method of claim 13 wherein sealing the first edge of the supportmember includes preventing the encapsulating material from passingbetween the first edge of the support member and the wall.
 15. Themethod of claim 13 wherein the aligning member includes an alignmentsurface that tapers relative to the interior wall of the mold, furthercomprising: engaging the microelectronic device with a support surfaceof the support member positioned between the first and second edges ofthe support member; and moving the alignment surface of the aligningmember along the engaging edge of the support member in a directiontransverse to a plane of the support surface.
 16. The method of claim13, further comprising cutting into the engaging edge of the supportmember with the aligning member.
 17. The method of claim 13 wherein themold has a first portion with the internal wall and a second portionseparable from the first portion along a mold line, the second portionhaving the aligning member, further comprising positioning the supportmember and the microelectronic device between the first and secondportions of the mold and moving at least one of the first and secondportions toward the other to engage the aligning member with the supportmember.
 18. The method of claim 13, further comprising inserting the pininto the concave recess by moving the pin toward the support member in adirection transverse to a surface of the support member engaged with themicroelectronic device.
 19. A method for encapsulating first and secondmicroelectronic devices, comprising: providing first and second supportmembers, each having a first edge, a second edge opposite the firstedge, and an engaging surface with at least a portion of the engagingsurface offset from the first and second edges, the engaging surface ofthe first support member being separated from the first edge of thefirst support member by a first distance, the engaging surface of thesecond support member being separated from the first edge of the secondsupport member by a second distance greater than the first distance byless than 200 microns; engaging the first microelectronic device withthe first support member and engaging the second microelectronic devicewith the second support member; positioning the first edge of the firstsupport member proximate to an internal wall of a mold; moving analigning member to a fixed position relative to the internal wall of themold; biasing the first edge of the first support member against theinternal wall of the mold by engaging the engaging surface of the firstmember with the aligning member of the mold; at least partiallyencapsulating the first microelectronic device by disposing anencapsulating material in the mold adjacent to the first microelectronicdevice and removing the first microelectronic device and the firstsupport member as a unit from the mold; positioning the first edge ofthe second support member proximate to the internal wall of a mold;moving the aligning member to the same fixed position relative to theinternal wall of the mold; biasing the first edge of the second supportmember against the internal wall of the mold by engaging the aligningmember of the mold with the engaging surface of the second supportmember; and at least partially encapsulating the second microelectronicdevice by disposing an encapsulating material in the mold adjacent tothe second microelectronic device and removing the secondmicroelectronic device and the second support member as a unit from themold.
 20. The method of claim 19, further comprising separating a firstportion of the mold having the aligning member from a second portion ofthe mold having the internal wall after removing the first supportmember and before positioning the second support member.
 21. The methodof claim 19 wherein biasing the first edge of the first support memberincludes preventing the encapsulating material from passing between thefirst edge of the first support member and the internal wall of the moldby forming a seal between the first edge of the first support member andthe internal wall.
 22. The method of claim 19 wherein providing a firstsupport member includes providing a first support member having aconcave aperture in the second edge of the first support member, a wallof the concave aperture defining the engaging surface of the firstsupport member.
 23. The method of claim 19 wherein the aligning memberincludes an alignment surface that tapers relative to the internal wallof the mold, further comprising: engaging the first microelectronicdevice with a support surface of the first support member positionedbetween the first and second edges of the first support member; andmoving the alignment surface of the aligning member along the engagingsurface of the first support member in a direction transverse to a planeof the support surface.
 24. The method of claim 19, further comprisingcutting into the engaging edge of the first support member with thealigning member.
 25. The method of claim 19, wherein providing the firstand second support members includes providing first and second supportmembers with the second distance greater than the first distance by 100microns or less.
 26. A method for encapsulating a microelectronicdevice, comprising: engaging the microelectronic device with a supportmember having a first edge, a second edge opposite the first edge, aplurality of index holes along at least one of the edges, and anengaging surface with at least a portion of the engaging surface spacedapart from the first and second edges and the index holes; positioningthe first edge of the support member proximate to a wall of a mold;moving an aligning member relative to the wall of the mold; biasing thefirst edge of the support member against the wall of the mold byengaging the aligning member with the portion of the engaging surfacespaced apart from the first and second edges; and at least partiallyencapsulating the microelectronic device by disposing an encapsulatingmaterial in the mold adjacent to the microelectronic device.
 27. Themethod of claim 26, further comprising preventing the encapsulatingmaterial from passing between the first edge of the support member andthe wall of the mold by forming a seal between the first edge of thesupport member and the wall of the mold.
 28. The method of claim 26wherein engaging the microelectronic device with a support memberincludes engaging the microelectronic device with a support memberhaving a concave aperture in the second edge of the support member, awall of the concave aperture defining the engaging surface.
 29. A methodfor forming a support member for supporting a microelectronic device,comprising: forming a first edge on the support member with the firstedge configured to engage an interior wall of a mold; forming a secondedge on the support member opposite the first edge with conductivematerial positioned between the first and second edges for coupling tothe microelectronic device; and forming an engaging surface on thesupport member such that the engaging surface is spaced apart from thefirst edge by a selected distance within a tolerance range and theengaging surface is spaced apart from the second surface, the engagingsurface being configured to engage an alignment member of the mold whenthe support member and the microelectronic device are placed in the moldand the first edge of the support member engages the interior wall ofthe mold.
 30. The method of claim 29 wherein forming the first edge ofthe support member includes routing the first edge.
 31. The method ofclaim 29 wherein forming the engaging surface includes forming agenerally circular aperture in the support member.
 32. The method ofclaim 29 wherein forming the engaging surface includes drilling a holein the support member with a wall of the hole defining the engagingsurface.
 33. The method of claim 29 wherein forming the engaging surfaceincludes drilling a hole through the support member with a drill bit.34. The method of claim 29 wherein forming the engaging surface includesdirecting a water jet toward the support member.
 35. The method of claim29 wherein forming the engaging surface includes directing a lasertoward the support member.
 36. The method of claim 29 wherein formingthe engaging surface includes forming the engaging surface with theselected distance having a tolerance range of □50 microns or less. 37.The method of claim 29 wherein the support member is a first supportmember defined by a first portion of a body of support member material,the body of support member material having a second portion adjacent thefirst portion, the second portion defining a second support member,further comprising: forming an aperture in the body of support membermaterial, the aperture having an aperture wall with a first part of theaperture wall defining the engaging surface of the first support memberand a second part of the aperture wall defining an engaging surface ofthe second support member; and separating the first portion of the bodyof support member material from the second portion of the body ofsupport member material to form the first and second support members.38. The method of claim 29, further comprising selecting the supportmember material to include a plastic laminate.
 39. The method of claim29 wherein the support member is a first support member, furthercomprising stacking the first support member on a second support memberand drilling a hole through the stacked support members to form engagingsurfaces in both support members.
 40. The method of claim 29 whereinforming the engaging surface includes forming a tab projecting away fromthe second edge of the support member, with the engaging surface definedby a surface of the tab.
 41. A method for forming a support member forsupporting a microelectronic device, comprising: forming a first edge onthe support member with the first edge configured to engage an interiorwall of a mold; forming a second edge on the support member opposite thefirst edge with conductive material positioned between the first andsecond edges for coupling to the microelectronic device; forming aplurality of index holes along at least one of the first and secondedges;and forming an engaging surface on the support member with theengaging surface spaced apart from the first edge by a selected distancehaving a tolerance range, the engaging surface being configured toengage an alignment member of the mold when the support member and themicroelectronic device are placed in the mold and the first edge of thesupport member engages the interior wall of the mold.
 42. The method ofclaim 41 wherein forming the engaging surface includes forming theengaging surface with the selected distance having a tolerance range of±50 microns or less.
 43. The method of claim 41 wherein forming theengaging surface includes forming a generally circular aperture in thesupport member.
 44. A method for forming a support member for amicroelectronic device, comprising: removing material from a firstportion of a perimeter of the support member to form a first edgeconfigured to engage an interior wall of a mold; removing material froma second portion of the perimeter of the support member to form a secondedge opposite the first edge; and drilling a hole through the supportmember to form an engaging surface of the support member, with theengaging surface spaced apart from the first edge by a selected distancewithin a tolerance range, the engaging surface being configured toengage an aligning member of the mold when the support member and amicroelectronic device are placed in the mold and the first edge of thesupport member engages the interior wall of the mold.
 45. The method ofclaim 44 wherein forming the engaging surface with the tolerance rangebeing ±50 microns or less.
 46. The method of claim 44 wherein formingthe first edge of the support member includes routing the first edge.47. The method of claim 44 wherein the support member is a first supportmember defined by a first portion of a body of support member material,the body of support member material having a second portion adjacent thefirst portion, the second portion defining a second support member,further comprising: drilling the hole in the body of support membermaterial with a first part of a wall of the hole defining the engagingsurface of the first support member and a second part of the walldefining an engaging surface of the second support member; andseparating the first portion of the body of support member material fromthe second portion of the support member material to form the first andsecond support members.
 48. A method for forming support members forsupporting microelectronic devices, comprising: forming an aperture in abody of support member material, the body having first and secondportions, the aperture having an aperture wall defining a first engagingsurface in the first portion and a second engaging surface in the secondportion; separating the first portion of the support material from thesecond portion along an axis that intersects the aperture to form aninner edge of each portion of the support member material; and formingan outer edge opposite the inner edge for each of the first and secondportions, with the first engaging surface separated from the outer edgeof the first portion by a distance having a tolerance of ±50 microns orless and the second engaging surface separated from the outer inner edgeof the second portion by a distance having a tolerance of ±50 microns orless.
 49. The method of claim 48 wherein forming an aperture includesforming a generally circular opening in the body of support membermaterial.
 50. The method of claim 48 wherein forming an apertureincludes drilling a hole through the body of support member materialwith a drill bit.
 51. The method of claim 48 wherein forming an apertureincludes directing a water jet toward the body of support membermaterial.
 52. The method of claim 48 wherein forming an apertureincludes directing a laser toward the body of support member material.53. The method of claim 48, further comprising selecting the body ofsupport member material to include a printed circuit board.
 54. Themethod of claim 48, further comprising selecting the body of supportmember material to include a conductive material for coupling to themicroelectronic devices.
 55. A support member for supporting amicroelectronic device in a mold, comprising a support member bodyhaving: a first surface configured to engage the microelectronic device;a second surface facing opposite the first surface; electricallyconductive material at the first and/or second surface and/or betweenthe first and second surfaces; a first edge between the first and secondsurfaces configured to engage an interior wall of the mold; a secondedge between the first and second surfaces facing opposite the firstedge; and an engaging surface configured to engage an aligning member ofthe mold, the engaging surface spaced apart from the first edge by aselected distance having a tolerance range.
 56. The support member ofclaim 55 wherein the tolerance range is □50 microns or less.
 57. Thesupport member of claim 55 wherein the second surface of the supportmember has a concave aperture, a wall of the concave aperture definingthe engaging surface.
 58. The support member of claim 55 wherein theengaging surface is defined at least in part by an aperture extendingthrough the support member and spaced apart from the first and secondedges.
 59. The support member of claim 55 wherein the engaging surfaceis defined at least in part by a hole drilled through the supportmember.
 60. The support member of claim 55 wherein the engaging surfaceis defined at least in part by a tab extending away from the second edgeof the support member.
 61. A support member for supporting amicroelectronic device in a mold, comprising a support member bodyhaving: a first surface configured to engage the microelectronic device;a second surface facing opposite the first surface; electricallyconductive material at the first and/or second surface and/or betweenthe first and second surfaces; a first edge between the first and secondsurfaces configured to engage an interior wall of the mold; a secondedge between the first and second surfaces facing opposite the firstedge; a plurality of index holes between the first and second edges; andan engaging surface configured to engage an aligning member of the mold,the engaging surface spaced apart from the first edge by a selecteddistance having a tolerance range.
 62. The support member of claim 61wherein the tolerance range is ±50 microns or less.
 63. The supportmember of claim 61 wherein the second surface of the support member hasa concave aperture, a wall of the concave aperture defining the engagingsurface.
 64. A microelectronic device package, comprising: a supportmember having a first edge, a second edge opposite the first edge, asupport surface between the first and second edges and an engagingsurface configured to engage an aligning member of a mold, the engagingsurface being spaced apart from the first edge by a selected distancehaving a tolerance range; a microelectronic device adjacent to thesupport surface of the support member; and a volume of encapsulatingmaterial disposed at least partially around the microelectronic device.65. The package of claim 64 wherein the tolerance range is □50 micronsor less.
 66. The package of claim 64 wherein the first edge of thesupport member includes a routed edge.
 67. The package of claim 64wherein the engaging surface includes a generally circular aperture inthe support member.
 68. The package of claim 64 wherein the engagingsurface includes a drilled hole in the support member with a wall of thehole defining the engaging surface.
 69. An apparatus for supporting amicroelectronic device during an encapsulation process, comprising: amold body having a cavity defined in part by a cavity wall; an aligningmember coupled to the mold body and positioned a first selected distancerelative to the cavity wall; and a support member having a first edgeengaged with the cavity wall and an engaging surface engaged with thealignment member, the first edge and the engaging surface beingseparated by a second selected distance having a tolerance range. 70.The apparatus of claim 69 wherein the tolerance range is ±50 microns orless.
 71. The apparatus of claim 69 wherein the aligning member has atapered alignment surface with the alignment surface spaced apart fromthe cavity wall by a first distance at a first location on the alignmentsurface, the alignment surface being spaced apart from the cavity wallby a second distance less than the first distance at a second locationcloser to the mold body than the first location.
 72. The apparatus ofclaim 69 wherein the mold body includes a first portion removablycoupled to a second portion, further wherein the cavity is positioned inthe first portion and the alignment member depends from the secondportion.
 73. The apparatus of claim 69 wherein the aligning member has agenerally rectangular cross-sectional shape.
 74. The apparatus of claim69 wherein the aligning member has a sharpened edge.
 75. The apparatusof claim 69 wherein the aligning member has a generally circularcross-sectional shape.